The major influencing factors of skin aging are intrinsic factors (such as age, gene mutation, cell metabolism, hormone environment) and extrinsic factors (such as chemicals, toxins, environmental pollution, ultraviolet, and ion rays). Most extrinsic skin aging is due to sun exposure. Photoaging results largely from the effects of UVA on the dermal matrix. 1,2 80% of UVA rays reach to the dermo-epidermal junction and penetrate deeper in the papillary dermis. 3,4 UVA exposure causes much more dermal matrix damage than UVB and eventually "solar elastosis" which leads to skin elasticity damage and loss.Collagen and elastin in the dermis are the main components of the extracellular matrix and constitute the dermal network structure and elasticity capability. It has been shown that approximately 50% of UV-induced photodamage is caused by reactive oxygen species (ROS) which is a common initial step in the damage caused by UVA,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.